Joseph w



(No Model.)

J. W. DAVIS.

STERN OP SCREW PROPELLER STEAMERS. No. 251,529,

Patented Dec. 27, 1881.

NVENTOR. i M

BY ATTORNEYS.

Pholo-Lilhugnpwr. Wahlngtun, I). C.

" UNITED STATES PATENT OFFICE.

JOSEPH V. DAVIS, OF PORT JEFFERSON, NEW YORK.

STERN OF SCREW-PROPELLER STEAMERS.

SPECIFICATION forming part of Letters Patent No. 251,529, dated December 27, 1881.

Application filed October 20, 1881. (No model.)

To all whom it may concern:

Be it known that I, JosEPH W. DAVIS, of Port Jefferson, in the county of Suffolk, Long Island, and State of New York, have invented a new and useful Improvement in the Sterns of ScrewPropeller Steamers, of which the following is a full, clear, and exact description.

The object of my invention is to provide a strong and rigid bearing for the outer ends of the propeller -shafts of steamboats having a propeller'shaft at each side of the rudder; and a further object of my invention is to prevent one screw from disturbing the water of the other screw.

The invention consists in a steamboat-hull constructed with three stern-posts, to the center one of which the rudder is pivoted, whereas the two screw-shafts have their hearings in the side stern-posts. The middle stern-post is a short distance longer or higher than the side stt-rn-posts.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in both the figures.

Figure 1 is a perspective View of the rear end of a steamboat provided with three sternposts. Fig. 2is a rear elevation of the same.

The steamboat-hull A is constructed with a middle stern-post, B, to which the rudder O is pivoted in the ordinary manner, and with two side stern-posts, D, equidistant from the sternpost B. In each stern-post D a propellershatt, E, is journaled, on which shafts E the propeller-screws F are mounted, these screws rotating in vertical openings G in the framework H, uniting the stern-posts with the hull and forming the side kecls, J, which do not extend along the entire bottom of the boat, as the center keel, K, does, but only extend from the bottom of the stern-posts D to the hull. The middle stern-post, B, extends downward a small distance more than the side stern-posts, D-that is to say, the distance from the deck L to the bottom ot'the middle stern-post, B, is greater than the distance from the deck to the bottom of the side stern-posts, D.

I am aware that steainboats with two screwpropellers have been constructed heretofore; but the outer end of the shafts did not have any bearing, and an undue strain was thus exerted on the shaft and its inner bearing. Steamboats have also been constructed with two side stern-posts, each provided with a rudder; but in this case one screw disturbed the water of the other so that the screws had to operatein disturbed and whirled water, which greatly impairs the effectiveness of the screws. All these defects are avoided by my construction. The outer end of the shafts have a strong bearing, and one screw cannot disturb the water of the other. as the middle stern-post, B, and the middle keel, K, are arranged between the two screws, so that each screw will have clean water, and will thus be very effective. Furthermore, the frame-work uniting the middle stern-post to the hull is not weakened by an opening for a screw as it is in the singlescrew steamers. If the steamer runs aground and lists to one side, the side stern-posts will not be broken, nor will the screw be damaged,

for the hull will rest on the center-keel and on the outer edge of the hull. The three keels break up the water, and the force of a sea against the hull is very much diminished, and consequently the vessel is not jarred nor strained as much as it the sea should strike it with full force.

I am aware that two propellers have been arranged under avesselon each side of the middle keel, for thepurpose of operating in water unbroken by the passage of the vessel; but

What I claim as new and of my invention A steamboat-hull having a medium post, B, carrying the pivoted rudder O and connecting with the keel K, and on each side of said rudderpost, a sternpost, D, and frame H, the latter provided with a screw-propeller, F, in a vertical opening, G, as shown and described.

- JOSEPH W. DAVIS. Witnesses:

Osoan F. GUNz, Tnos. J. RITCH,J r. 

